Chadarnook is a boss fight in Owzer's Mansion in the World of Ruin. It is a demon possessing a painting of the esper Lakshmi. Chadarnook alternates between Goddess and Demon forms, and the Demon form must be defeated to finish the battle, as the Goddess form will regenerate her HP when killed.
Chadarnook is the boss of Sigmascape V2.0 and its Savage version. Only the demon can be attacked while the goddess will continuously use a ranged attack on the second tank. The demon can possess the four paintings in the room and the attacks used depends on which paintings are being possessed. The demon can possess two paintings at once. The demon also has a tank buster and a roomwide AoE attack independent of paintings.
In the savage version, the goddess takes a more active role. While she still cannot be attacked, she can possess paintings with different mechanics compared to the demon. She also gains more abilities, such as summoning an add that will follow a healer for some time, instantly knocking them out if coming to contact.
Chadarnook is fought during the A Lost Painting hunt in Altissia. Vyv Dorden in Lestallum requests the party to take a photo of it. It resists physical attacks but is weak to Fire. The bestiary implies that the goddess part of the ghost is the woman depicted in the painting, called Lakshmi in allusion to Final Fantasy VI.
Chadarnook appears as a water-elemental Eidolon for the Deathlord. It teaches the Deathlord Cursra
abilities and has the Consuming Mist summon attack. Chadarnook's signet artwork is based on its original appearance from Final Fantasy VI.